The primary goal of this project is to uncover physiological and anatomical correlates of amblyopia in both humans and monkeys. This will continue the P.I.'s previous grant concerning the structure of ocular dominance columns (ODC) in animals and humans. There are 5 new specific aims that he will investigate: (1) The effect of strabismus on periodicity of ocular dominance columns, (2) Possible disruption of intrinsic connections from layer 4C to layer 3 in V1, (3) Alterations in human amblyopes of the complete pattern of ODC's, the organization of CO stripes in V2, and the organization of other extrastriate visual areas, (4) the cortical locus of visual suppression in strabismus and (5) the identity of a visual area anterior to macaque dorsal V2 that contains a unique CO pattern. Together, these new experiments will extend the previous work by investigating mechanisms beyond the ODC's that might be responsible for the poor vision in amblyopia.